COMPLETE DENTURE PROSTHODONTICS
A Manual For Clinical Procedures
Bernard Levin, D.D.S., M.Ed., Professor Emeritus
Glenn D. Richardson, D.D.S., M.S., Associate Professor Emeritus
University of Southern California School of
Dentistry
TABLE OF CONTENTS Page 1 Acknowledgments
...
Goals...
General Policies...
Assignment of Patients...
Types of Denture Service
...
Diagnosis and Treatment Planning...
Length of Treatment Time and Appointments
. .
...
Clln~cal Requirements
...
.:
...
Frank M.Lott and Bernard Levin Awards
...
Outline of Denture Technique...
First Visit-
Diagnosis, Prognosis, and Preliminary Impressions...
Diagnosis and Prognosis
...
Exarr~ination-
Diagnostic Aids, Age, Sex, and Occupation ...Edentulous History, Residual ridge, and Ridge Relationship
...
Palatal Seal Area
...
Gag Reflex, Border Attachments, and Soft Tissues...
Tongue Position, and Mobility of Floor of Mouth... Lateral Throat Form and Saliva
...
Amount of Saliva, Radiograms, and Attitude of Patient ...
Commmunicating With Patients
...
Surgical Corrections
.
and Prognosis...
.
Preliminary Impressions...
Mandibular... Maxillary... Patients 'That Gag Easily ...
Pouring Im~pressions
...
Trimming of Casts
...
Fabrication of Custom Impression Trays ...
Second Visit = Final Impressions
...
Border Molding
...
Use of Impression Stick Compound...
... Use of Heavy-Bodied Putty...
Border molding of Mandibular Tray...
Final Mandibular Impression
...
Border Molding of Maxillary Tray
...
Final Maxillary Impression
...
Boxing and Pouring...
Separating Casts
...
Keying Casts
...
Fabrication of Baseplates
...
Page2
Third Visit
.
Occlusal Plane. Vertical Dimension. Centric Relation.Face-Bow Transfer. Mid.Line. Smile Line. and Selection of Teeth ... 57
Occlusal Plane
...
58Vertical Dimension
...
60Face-Bow Transfer
...
62Centric Relation
...
67Mounting the Maxillary Cast ... 69
Mounting the Mandibular Cast
...
70Selection of Anterior Tetth
...
73Porcelain or Resin
...
74Shade Selection
...
74Mold Selection
...
75Ordering Teeth
...
83Selection of Posterior Teeth
...
84Set-Up Optional Visit: Arangement of Anterior Teeth
...
86Evaluation of Anterior Teeth ... 92
Re-Shaping of Teeth ... 92
Arrangement of Anterior Teeth If Nott Done As An Optional Visit ... 92
Arangement of Posterior Teeth
...
93Fourth Visit
-
Evauate Occlusal Plane. Centric Relation. Vertical Dimension and Esthetics. Patient's Acceptance of Tooth Arrangement. Posterior Palatal Seal. and Protrusive...
96Occlusal Plane
...
97Vertical Dimension ... 98
Centric Relation ... 98
Correcting an Incorrect Mounting ... 98
Esthetics... 99
Protrusive Record ... 100
Posterior Palatal Seal ... 102
Festooning... 105
Remount Record For Maxillary Denture
...
112Utilization of Commercial Laboratory
...
112Examination of dentures upon return from laboratory
...
114Remount casts
...
114Care of dentures after polishing
...
11FifthVisit
-
Insertion of Finished Dentures...
115Centric Relation Record
...
117Equilibrate Occlusion
...
119Instructions To Patient
...
122Adjustment Appointment
...
124Discussion of results with your instructor ... 125
Post-Insertion Problems
...
126Page3 Immediate Dentures
...
First Appointment: Preliminary Impressions
...
Fabrication of Custom Impression Tray
...
Second Appointment: Final Impressions
...
Fabrication of Occlusion Rims
...
Third Appointment: Occlusal Plane. Vertical Dimension. Face.bow. C.R. Record. Selection of Teeth
...
Cast Preparation and Arrangement of Anterior Teeth
...
Arrangement of Posterior Teeth and Wax-Up
...
Fourth Appointment: Insertion of Dentures
...
Post-Insertion Adjustments
...
Overdentures...
Advantages... Disadvantages
. .
...
Ind~cat~ons... Selection of Supporting Teeth
...
Procedures
...
Insertion
...
Abutment Relines
...
Reline and Rebase Technique...
Use of Visco-Gel
...
Procedure
...
Denture Repairs...
Fractured Dentures
...
Replacing a Broken Tooth
...
Border Molding with Adaptol and Vinyl Siloxane Putty...
ACKNOWLEDGMENTS
The authors are grateful for the help and suggestions of the Prosthodontic faculty, especially Drs.Phillip Reitz, John Sanders, and Larry Kaplan. Our sincere thanks to the Department of Audio-Visual Services, especially Mr. Martin Fong and his staff. To Mr. Carlos Serret and Mr. Udo Ahrndt a big thanks for their laboratory procedure advice for the construction of the trays, baseplates, etc. To Mr. Mark Greenridge of the Restorative Department for his help in the original typing of this manual.
We are indebted to the Dentsply Co. for photographs and sketches, and the Teledyne Co. for sketches and write-ups on their articulator. We are indebted to Dr.Robert Lee and the Panadent Corp. for their permission to use their drawings and instructions on the use of their face-bow.
A few comments from Dr. Levin: 'The first manual was written in 1966 and had
38pages It described the procedures for complete and immediate dentures, and
there were no illustrations. Later editions included relines and a some illustrations. In '72 we included a new concept (at 'that time), "Overdentures", and had 15
illustrations. The editions between '73 and '84 were mainly updating and gradually adding more line drawings. In '93 we added a detailed and illustrated section on arranging the anterior teeth and denture repairs. 'This 2002 edition has 174 pages and 76 illustrations, not counting mold charts, and patient treatment forms and
handouts. New subjects are post-insertion problems and solutions. commur~icating with patients, putty border molding, and denture adhesives.
Recommended References:
Boucher's Prosthodontic Treatment For Edentulous Patients. Carl Boucher et al, 10th Edition. Classic and comprehensive.
Impressions for Complete Dentures, B. Levin. Out of print but available from USC Book Store.
INTRODUCTION
GOALS OF REMOVABLE PROSTHODONTICS:
1. The primary goal of the School of Dentistry is to prepare dental students to become restorative dentists capable of competer~lly performing basic
fundamental procedures of prevention and therapy in all phases of dentistry.
2. Dental students will learn to manage and treat the partially and fully edentulous patient so the patient is restored to a state of health, and the structures
remaining will be esthetically and functionally sound, and according to current accepted treatment protocols.
Complete denture service contributes to the general health of the patient by restoring the gnathostomatic system in a functionally healthy and comfortable
condition. The parts of this system, though considerably mutilated in the edentulous condition, nevertheless must be maintained in health and comfort. Surrounding this system is a whole patient with fears and apprehensions, and possibly with phobias, stuttering, poor speech, and malposed musculature, as well as many other tensions and concomitant disorders to which we are all prone even in the dent~~lous state. Therefore, in attempting the restoration of this system to a prosthodontic form of health it behooves us to know everything regarding the problem of the patient's health and general well-being, to the end that our efforts will prove successful. There must be mutual trust and understanding, and a rapport must be established between patient and doctor. It is important to like people and respond to reason- able demands and desires. While a well-executed dental restoration is the hallmark of a clinically sound procedure, this may be inadequate for a complete denture patient. Although a "mechanically perfect" denture prosthesis may be fabricated, the patient may not tolerate or adapt to it. The underlying problem may be physical or emotional.
It is very important to involve the patient during the complete denture fabrication process, especially at those check points where his or her acceptance and comfort are essential. A viable dentist-patient interaction is thus a requisite to achieving successful results.
It is also important to develop the knowledge and skill in all the mechanical and technical skills that are utilized in the treatment of the edentulous patient.
You cannot have the rapport and confidence of your patient if you are uncertain and fumbling. This manual is an important guide for your laboratory and clinical
procedures and have it in your cubicle for each visit. Studv it well before atterr~pting any dental procedure! Much thought and effort has been expended to make your task easier.
There are many acceptable methods of making dentures but you can imagine the confusion if all the methods were taught. It is our fond hope that you will either learn or even originate a better denture technique, but meanwhile we are confident that you will obtain excellent results with this basic technique. When unusual mouth or physchological conditions may necessitate a change from this basic method, your instructor will advise you how to proceed.
GENERAL POLICIES:
1. Most im~ortant: Patient treatment must be done with the highest levels of professional conduct and should always be characterized by courtesy and respect.
2. The school denture technique will be used for all cases, except in unusual situations and at the discretion of the instructor. Studv 'the clinic manual so we
can standardize our procedures.
3. Students are reminded that 'the primary function of a dental school is the education of students. Patients that are difficult for various reasons will be dismissed (faculty member only) at the diagnosis visit or later, if necessary.
4. All complete and irrtmediate dentures will be inserted in six weeks or less, except in cases of illness or any other valid situation.
5. An instructor will have the option
not
to supervise a student who does not have-
all his necessary instruments and materials available at the unit and this manual on the back bench and open for the appropriate visit. Precious time is wasted when a student has to rattle around histher cabinet or go elsewhere to find an instrument, or go to the dispensary for some required material.6. An entry must be made in the clinical record for each appointment. It will be signed by the student and the instructor. It is the students responsibility to obtain the instructor's signature. Make certain the Therapy Record is recorded and signed by you and your instructor as this record will always remain in the file.
7. It is very important to collect 113 down, 1/3 after the trial denture, and the final payment before placement of the completed denture. You will find out that in school (and in private practice) the fee is difficult, often impossible, to collect after the prosthesis has been inserted.
10. Make certain to make detailed notes of any unusual difficulties or recommendations on the treatment record.
11. The denture may be graded for final credit after the case has been in the mouth free of irritation for no less than one week.
ASSIGNMENT OF PATIENTS:
Unfortunately, we never have too many denture patients since there are numerous other convenient sources of treatment in the Los Angeles area. We have had a very favorable experience with treatment for close farrrily members and friends. These people will often prefer to have your dental services later, so you would be doing them and yourself a favor by treatment here where you will have the benefit of advice and counsel. Students must share some of the responsibility and try to obtain suitable clinic patients.
TYPES OF DENTURE SERVICE: Four types of denture services
1. Complete dentures
2. Immediate dentures
3. Overdentures
4. Implants (usually treated by graduate students but there is
DIAGNOSIS AND TREATMENT PLANNING:
After receiving the patient's chart, and if the treatment is obviously a complete or immediate denture, an appointment is made for what we call an "informal" or "tentative diagnosis."
Find out what days are best for future appointments. If possible, it is very important that you work with the same instructor for each removable prosthodontic case (complete dentures, immediate dentures, overdentures, and removable partial dentures). Working with one instructor will provide better continuity and fairer grading. Most of our patients with unsatisfactory results have been treated by students who made appointments at their convenience and used different
instructors. This often ends up with a variance of opinions, a great loss of time, and often a remake.
The first visit will tell you if your patient needs a denture, partial denture,
overdenture or implant. Sometimes it's easy call but often an experienced dentist will want to ponder awhile. If time is limited you should at chat with your patient and get to know himher better, and make a cursory inspection of the ridges and oral structures.
COMPLETE DENTURES: An exarrrination of the ridges and oral structures is needed to determined if the patient can be successfully treated by an
undergraduate student. Usually high expectations that are not realistic or other psychological problems are the cause of most failures. Only instructors will
determine if the patient is eligible for treatment here. Your Group Administrator will refer the patient to graduate Prosthodontics, outside dentist, or whatever would help the patient the most. You will soon observe that most ~atients are verv treatable.
IMMEDIATE DENTURE: An immediate denture is one that is fabricated before the teeth are extracted. Many patients prefer this as they are unwilling to be seen without teeth. The initial judgment of whether or not the treatment is an immediate denture will be made by an instructor. Make certain that you and the patient are aware of the fact that this is only a tentative diagnosis. Sometimes it is possible to make a much more satisfactory prosthesis, such as a removable partial denture, an overdenture, or even an implant, i.e., if the patient is willing to undergo extra
treatment and expense.
If it is possible to change the treatment plan to a fixed or removable partial denture or an overdenture, a consultation will be needed with a designated "facilitator" from Fixed, Removable.or Implant Prosthodontics. A periodontal evaluation now is very important. For an obvious immediate denture, it is not necessary for the periodontal evaluation.
If the final treatment plan is corr~plete irr~mediate dentures, your instructor will make the proper notation on the treatment plan along with the estimated fee.
Do not extract anv posterior teeth or do any procedure until an instructor has finalized the treatment plan.
OVERDENTURES: In the past, periodontally weakened teeth were usually extracted. An overdenture is a complete denture that is fabricated over retained teeth. 'These teeth are treated with periodontics and endodontics, and then
shortened. Patients who have been tentatively diagnosed for immediate corr~plete denture should be considered for this more satisfactory prosthesis. Teeth used for support should be teeth that have a crowniroot ratio so poor that the prognosis for a fixed or partial denture appliance is not possible. 'The patient must understand the risk of losing overdenture abutment teeth but the retention of these teeth is very advantageous.
LENGTH OF TREATMENT TIME AND APPOINTMENTS:
Denture patients usually have a history of indifference and neglect and is often the cause of the edentulous situation. However, once denture treatment has been started, the patient is usually very anxious to have the prosthesis. It is very discouraging when the treatment is extended too long. Once the treatment is started, you have a moral obligation to finish the case as quickly as possible. Whenever possible see the patient twice a week. There are few valid excuses for taking longer than six weeks to complete the denture. Block assignments are given well in advance and could delay treatment, so denture patients require special care when scheduling.
Most of the denture procedures will require three hours in the morning or afternoon session. Do not waste precious time by scheduling a long visit for an adjustment, or other short procedures. Occasionally patients will not return for the final
examination and grade. A final grade will be signed by the instructor only after the student has sent an appropriate letter to the patient and he/she still does not return.
CLINICAL REQUIREMENTS: As specified and will be posted. A good clinical experience would be:
Complete denture ,2 sets or 4 singles combined with RPD, overdenture, etc. Immediate denture, at least 1.
Overdenture, at least 1
.
Removable partial denture, 4 (2 should be distal extension cases). Treatment partial denture, at least 2.
Processed complete denture reline or rebase, at least 2.
Processed partial denture reline or rebase, 1.
Complete denture repair (add a tooth repair crack or add PPS, 1.
Partial denture repair (add a tooth or clasp), 1.
MISCELLANEOUS:
1. Complete denture and denture reline insertions must be corr~pleted no later than one week prior to final examination week and two weeks for immediate dentures. This does not include adjustments.
2. Maxillary and mandibular relines (or rebases) must be done separately. This is necessary because of the possibility increasing the occlusal vertical
dimension or losing the centric relation position.
3. Except for graduating seniors, the student who completed the denture will be responsible for all future adjustments, relines, and repairs. This is especially necessary for immediate denture patients.
SPECIAL AWARDS:
The Frank M. Lott Prosthodontics Award is given to the graduating senior who shows the most interest and proficiency in complete and removable partial dentures.
The Bernard Levin Prosthodontics Award is given to the graduating senior who has shown the most interet in removable prosthodontics during his four year program.
OUTLINE OF CLINICAL COMPLETE DENTURE TECHNIQLIE:
1st Visit: Patient interview, review health history, clinical and radiographic examination, diagnosis and prognosis, and patient education Preliminary impressions with alginate
Select teeth (optional)
Lab: Pour impressions with yellow stone and trim casts
Outline for custom tray Fabrication of custom tray
2nd Visit: Adjust tray borders Border mold
Final impressions Select teeth (optional)
Lab: Box impressions
Pour impressions with vacuum-mixed yellow stone Trim and key casts
Fabricate record bases with occlusion rims
3rd Visit: Adjust maxillary occlusion rim to correct lip level, parallel ala-tragus line and inter-pupillary line
Measure physiologic rest position Evaluate previous dentures
Adjust mandibular occlusion rim to a tentative O.V.D. Face-bow record
Record centric relation at O.V.D. Select teeth
Lab: Mount casts
Complete set-up
Optional Visit: Arrange anterior teeth (recommended if good esthetics especially needed)
4th Visit: Finalize Occlusal Vertical dimension: External measurements
Phonetics Swallowing
Facial appearance and comfort Prove centric relation
Protrusive record
-
set condylar guidances Locate and carve posterior palatal sealEsthetic evaluation
-
patient approval most importantLab: Complete arrangement of teeth in balanced occlusion
Complete wax-up
Make plaster index for face-bow record Separate master casts from mountings Laboratory processing and polishing Make plaster remount casts
Mount maxillary denture using plaster index
5th Visit: Insert dentures
Have patient bite on cotton rolls for at least 10 minutes Check adaptation with pressure disclosing paste Inter-occlusal centric relation record
Lab: M o ~ ~ n tmandibular denture
Equilibrate occlusion Polish
6th, 7th, etc. Visits: Adjustments and final evaluation
Note: Appoint the patient at 9 a.m. or 1:30 p.m. so you have the entire morning or afternoon for each major appointment. This will allow you time for some of the lab procedures. This is especially necessary when making impressions or recording jaw relations.
NOTE: Obtain the treatment form "Complete Denture Prosthesis Record". Sample on following page.
i
UNIVERSITY OF SOUTHERN CALIFORNIA SCHOOL OF DENTISTRY
Complete Denture Prosthesis Record
- .
Student ...No...Patient ...No ...
.Assigned Instructor ... No...Type of Case ... Fee ...
(Do not shut step 2 w ~ b u tan assignedinstructor)
Remarks: . . .
. . . -.> NOTE: All clinical and laboratory procedures must be signed by an i instructor. ALL procedures marked with an asterisk (*) must be
signed. by your assigned instructor.
I
Procedure Sequence I Grade (circle) I Initials I Date I Insuuctor's Comments.
I I I I
I I I I
1. Initial Interview J
-*2. Diagnosis and prognosis 4 3 2 1
"3. Prelimary impression-max 4 3 2 1
*4. Preliminary impression-man 4 3 2 1
5. Preliminary cast(s) trimmed with outline for tray(s) 6. Custom tray(s) fabricated 7. Border molded tray -max
*9. Final impression -max 1 4 3 2 1 I I I
* 10. Final impression
-
man 1 4 3 2 1I I. Master cast(s) trimmed & indexed
I
I I I 12. Record base(sl with occlusion Ir i d s ) fabricated
I
I
1
1 3. Occlusal plane
I
I
I
14. Face-bow
* 15. Occlusal vertical dimension 4 ' 3 2 1
* 16. Centric relation recorded 4 3 2 1
17. Teeth selected
18. Anterior tooth arrangement 1 9. Posterior tooth arrangement
*20. Examination of trial denture(s) 4 3 3 1 I approve of the color, shape and arrangement of the teeth
in mouth in wax dentures.
7 1. Protrusive record 22. Articulator set
23. Posterior palatal seal (Patient's signature and Date)
24. Final set-up and wax-up 25. Laboratory remount
26. Denture(s) polished I I
"27. Placement: tissue adaotation 1 4 3 2 1 I
remount, occlusal equiiibration
I
I
I
I
28. 24 hr ~ o s t la cement tissueadaptahon and articulation check
ADJUSTMENTS:
*29. Final adaptation. polish 4 3 2 1
and articulation check 30. Reline (if indicated)
FIRST VISIT
DIAGNOSIS, PROGNOSIS, AND PRELIMINARY IMPRESSIONS
Materials Needed:
I. Edentulous trays 7. Vaseline
2. Rubber bowl
-
large 8. Alginate impression material3. Plaster spatula 9. Water measure
4. Mouthwash 10. Periphery wax
5. 2 x 2 gauze 11. Sharp knife
6. Mouth mirror 12. Indelible pencil
13. Periphery wax
NOTE: This manual must be open for reference and available for every clinic visit.
DIAGNOSIS AND PROGNOSIS:
I. Review the general health history from the initial examination.
2. Younger patients usually have better health, neurorr~uscular control and adaptive capacity, and therefore have a more favorable prognosis.
3. Men are usually better patients as they are occupied with their work and have less time to fret about their dentures. Women tend to scr~~tinize their dentures and are more particular about esthetics. Nearly always, the most difficult patients are the pre-menopausal and post-menopausal women as they often have psychological problems and symptoms such as dry mouth, burning sensations, loquacious, vague pains, etc.
4. Stressful employment often complicates the adjustment to wearing dentures (example
-
bruxing).EXAMINATION OF PATIENT:
Most students (and dentists!) are anxious to get started, i.e., take impressions. However, a thoughtful diagnosis and prognosis are essential for success.
Review all of the following: it will take about 15-20 min. but will be time well spent. Experienced dentists can do this in 4-5min. Note any unfavorable factors and record on the denture record.
Read ~ a a e s 20-22 on Patient Communication before ~roceedina. -.. -.
1. EDENTULOUS HISTORY RECORD: Record the age of the present dentures, the number of previous dentures, success of previous denture, and the nature of complaints. The length of time edentulous (years) and previous dentures
(number) should be correlated. For example, if the patient has been edentulous for 20 years with no previous denture, the prognosis is poor. If this same
patient had 1 or 2 previous dentures and they were satisfactory, the prognosis is good. If this same patient had 5 or more sets of dentures, the prognosis is poor.
If a patient had partial dentures, inquire if they were satisfactory or not. If there were problems, or if the partial dentures were not utilized, make certain to record this. We cannot over err^ pliasize the importance of obtaining a detailed account
of the previous denture history, especially if there were problems.
IMPORTANT: It is very advantageous to make alginate impressions of both dentures ((external surfaces and teeth), make stone casts as these will be an exact copy of the original dentures. This especially useful if the patient was satisfied with the dentures. They are very useful for tooth selection, tooth arrangements, arch form, etc. They are very convenient when fabricating the wax occlusior~ rims. Your lab technician (when in private practice) will greatly appreciate these valuable guides.
2 RESIDUAL RIDGE: A square arch is the most favorable for retention and stability. The ovoid arch is slightly less favorable and 'the tapering arch is the least favorable. A broad ridge is the most favorable. Irregular ridges with undercuts or sharp projections may require surgical correction. A flat lower ridge is usually difficult but can be managed if the patient has a favorable tongue position and a wide buccal shelf. The most difficult ridge is thin and knife-edged, especially the mandibular. This is usually seen in a tapered arch with sharp mylohyoid ridges and narrow buccal shelves.
3. RESIDUAL RIDGE RELATIONSHIP: Class II or retrogna'thic is usually difficult as the patient looks toothy, often holds the mandible forward to improve
appearance with subsequent TMJ problems, usually have a great range of jaw movements in function, require careful occlusion, and usually needs a large interocclusal distance. Class Ill or prognathic is usually easier if not extreme. The patient usually functions on a hinge (little or no protrusive component) and requires a minimum of interocclusal distance. In any case, do not set the teeth
for a retrognathic or prognathic patient in a normal relationship, unless there is only a moderate deviation from Class I.
4 PALATAL VAULT FORM: A flat palate has good vertical support but provides
little resistance to lateral shifts.
A high (or "V-shaped") palate resists lateral shifts well, but vertical displacement tends to break the seal in all areas at once. Gagging is more common and processing shrinkage is greater. Fortunately, this vault form is uncommon.
A curved or "U-shaped" palate provides the most favorable prognosis and resists both vertical and lateral displacement.
5 TOR US PALATI NUS: Does not require surgical intervention unless large and bulbous. Even in this case, a roofless denture can be made ifthe ridge is good and the patient has reasonable coordination.
The mucosa over a torus is usually thin and unyielding. Arbitrary relief (often
used in past years) is not used. The correct relief is obtained by the use of pressure indicator paste in the finished denture.
6. MANDIBULAR TORUS: Usually more of a problem as it interferes with 'the lingual border seal and a denture would restrict the tongue space. Surgical correction is indicated if prominent and especially if undercut.
7. AVAILABLE POSTERIOR PALATAL SEAL AREA: A wider and deeper posterior palatal seal area is more favorable for retention. The posterior palatal areas were described and classified by M. M. House.
JUNCIWN OF HARD AND SOFF P W
CLASS l
CLASS Ill
7
Class I : Large and normal in form with soft tissue extending posteriorly from the hard palate for 5-12 rnm., at which point the curtain of the soft palate. becomes movable (called the "ah" line) with a decidedly large range of movement.
Class II: Medium and normal in form, having movable tissue approximately 3-5 mm. posterior to the hard palate.
Class Ill: Small and with little or no movable tissue posterior to the hard palate, with the soft palate turning down abruptly within 1 mm. of the junction
of the hard and soft palates.
Class I offers the largest area for the palatal seal and Class II somewhat less; both are favorable as the posterior seal can be placed in soft tissue. Class Ill has little movable soft tissue posterior to the hard palate and it is not possible to place a conventional posterior seal. In this case, a posterior double bead is the seal of choice. The most common palate form is the Class 11.
8 GAG REFLEX: Evaluated by lightly running a mouth mirror over the soft palate. A slight or no response is most favorable. Moderate gagging can usually be controlled by careful denture procedures, counseling and even medication. Severe gaggers have a poor prognosis and should be evaluated carefully as they usually cannot be treated by an under-graduate student.
9. BORDER TISSUE ATTACHMENTS: A low position (away from crest) is most
favorable for developing and maintaining a good border seal. High
membranous and muscle attachments (near the crest of the ridge) are less favorable. Surgical corrections are possible but difficult as scarring and
re-attachment can occur. Frenum attachments are only significant if high
(w
t- S~~urgicalcorrection of frenums are not difficult.
SOFT TISSUES: Normal tissue is about 2 mm. thick, evenly distributed over the ridge and has normal color and appearance. Hard (thin and unyielding) tissue is usually seen in geriatric patients and presents problems with retention and soreness.
Soft spongy tissue (gingival hyperplasia) is most often seen in the maxillary anterior area, especially when the patient had a maxillary denture and
mandibular natural anterior teeth. This tissue can be surgically removed but the result is an anterior ridge with little or no vestibule. A surgical procedure is possible to deepen the vestibule but must be done as a graduate procedure. Inflamed soft tissue (denture stomatitis) requires caref~ll consideration as it may be due to ill-fitting dentures, excessive vertical dimension, bruxing, allergies, etc., or systemic conditions. Papillary hyperplasia is often seen when a patient has an ill-fitting maxillary denture or rarely removes the denture for cleaning or tissue rest. NOTE: If the patient has any of the above, discuss this
11. TONGUE POSITION: This is a very important consideration that has been largely neglected, and is of great interest to prosthodontists. To evaluate, instruct the patient to open just enough for a small portion of food and observe the tongue carefully. In the normal position, the tongue is relaxed, completely fills the mandibular arch, and the apex lightly contacts the lingual of the
mandibular teeth. This position is most favorable for maintaining the lingual border seal and retention. In some you can see the patient holding the denture down with the tongue.
The patient with a retruded tongue will have a poor lingual seal andusually has a poor mandibular denture prognosis unless this condition is improved. The simplest treatment is to tack on a small bit of self-curing resin on the anterior lingual flange, a few mm apical and lingual to the mandibular central incisors, using the old denture. The patient is asked to keep histher tongue in contact with the resin, except when eating and speaking. If or when the retruded tongue position improves (usually 2-3 weeks), the raised resin area is easily removed and polished. It is an easy procedure and worth trying when
indicated. Most patients are surprised and pleased with the improvement.
12 FUNCTIONAL MOBILITY OF FLOOR OF MOUTH: A very important diagnostic
aid and not difficult to determine. If the floor of the mouth remains at about the same level during swallowing, denture seal is usually easier to obtain, and conversely more difficult to obtain if the movement is large. The easiest procedure is to observe or palpate the hyoid bone during a swallowing
movement and the amount of movement is easily observed. Also palpate the floor of the mouth to evaluate it's displaceability. Some are quite soft and others feel quite taunt. This will be one of the deterruining factors of the length of the lingual borders.
The posterior lingual area is called the retromylohyoid fossa and is an area important for stability and peripheral seal (see below).
The retromylohyoid fossa (lateral throat form) depth and width in moderate function is estimated by placing a mouth mirror (which is about as thick as a denture) in the disto-lingual vestibule. This has been classified by Ewell Neil :
Class I The mouth mirror is not visible when the tongue is in a slightly protruded position; most favorable for retention and stability.
Class II One half of the mouth mirror is visible; less favorable.
Class Ill 'The entire mouth mirror is visible; least favorable.
ANATOMY OF DISTO-LINGUAL VESTIBULE
1. Mylohyoid muscle
-2. Palatoglossus muscle 3. Superior constrictor muscle 4 Pterygomandibular raphe 5. Buccinator muscle
13. CHARACTER OF SAI-IVA: Normal amount and viscosity is the most favorable.
Thin watery saliva is best in theory but a mix that includes some viscous saliva will provide the best retention. Thick ropy saliva corr~plicates impression taking and is annoying to the patient as it clings to the denture.
14. AMOUNT OF SALIVA: Excessive saliva is common when the denture is first inserted but usually improves in time. Deficient saliva (xerostomia) is often seen in geriatric patients who have certain systemic disorders and are taking medications, and resl-]Its in a poor prognosis for denture retention and comfort. No saliva is the most serious problem and is usually the result of radiation for oral cancer. This patient would require special care and should be treated in Graduate Prosthodontics.
15. PROMINENCE OF MAXILLARY AN'TERIOR RIDGE: If the maxillary anterior
ridge is prominent and undercut, a decision must be made whether to use a "flangeless" or short flange denture, or if an alveoplasty is best. This decision is often necessary for immediate dentures.
16 RADIOGRAPHIC: Examine the radiograms carefully and note any
abnormalities. Retained roots with no apparent pathology can often be left alone provided the patient is informed of their presence and x-rayed
periodically.
17. ATTITUDE OF PATIENT: A simple and practical classification has been described by M. M. House:
Class I : Philosophical
a. Those who have presented themselves prior to the extraction of their teeth, have no experience in wearing artificial dentures and do not anticipate any special difficulties in that regard.
b. Those who have worn satisfactory dentures, are in good health, are a well- balanced type, and are in need of further denture service.
Class 2: Exacting
a. Those who, while suffering ill health, are seriously concerned about the appearance and efficiency of artiaficial dentures. They are, therefore, reluctant to accept the advice of the physician and the dentist and are unwilling to submit to the removal of their natural teeth.
b. Those wearing arti'ficial dentures unsatisfactory in appearance and usefulness, and who so doubt the ability of the operator to render a service which will be satisfactory that they often insist on a written
Class 3: Hysterical
a. Those in bad health with long neglected pathological mouth conditions, and who dread dental service and submit to the removal of their teeth as a last resort and who are positive in their minds that they can never wear artificial dentures.
b. Those who have attempted to wear artificial dentures but failed and are thoroughly discouraged. They are of a hysterical, nervous, very exacting
temperament and will demand efficiency and appearance from *the artificial denture equal to that of the most perfect natural teeth. Class 4: Indifferent
Those who are unconcerned about their appearance and feel very little or no necessity for teeth for mastication. 'They are therefore non-
persevering, and will inconvenience themselves very little, if at all, to become accustomed to dentures.
Class I and II patients are nearly always treatable, even with poor ridges and other oral handicaps, and Class Ill and IVs are usually 'the most difficult.
PROGNOSIS: It is often difficult to make a correct prognosis, even for an
experienced dentist. If the patient has any of .the negative factors described (poor ridges, flabby tissue, etc.) that can be a barrier to successful dentures, these must be pointed out and.explained NOW. If they are pointed out after the dentures are com~leted, you will sound like you are making excuses. The limitation of dentures must be pointed out (limited mastication, not a face lift, etc.).
COMMUNICATING WITH PATIENTS:
The ability to communicate effectively and explain the problems of wearing dentures is undoubtedly one of the primary factors for successful treatment. You can be sure you are going to have
this type of patient in your chair and you
better have some straight answers. RE SO GOOD,
Often the problem is with a patients with poor ridges, poor coordination, etc., but they don't want to hear that. 'They will
say you made a set for their aunt Tillie and she says they are perfect! "You can do the same (a denture is a denture, ain't it ?)".
-
Now is the time to educate the patient to the fact that every mouth is different.These patients have realistic concerns and need to know why are they having problems and what can be done about them.
Now comes the difficult part: communication. It is necessary to explain what causes these problems and what can be done or what can't be done. The art and science of communication have become very important and large corporations will pay millions to "connect" with their clients. We aren't in their position but we can "connect" by using some old fashioned common sense.
1. Talk about the problem and possible solution in layman terms. Avoid words as vertical dimension, centric occlusion, etc. Talk about the height of the face,
the way the teeth come together, etc. --
-2. Use analogies as much as possible. The cartoon
is good but the caption is bad. Talk about a wide, rounded jaw, a thin, sharp edged jaw, or a flat jaw. Explain there is a big difference between
sitting on a large log or a narrow plank. Save some old casts that have the different ridge forms so the
8 DEUTURE RESTlNC bU CI
patient can see and even feel the difference. BROBD eRsE OR RI'IME W I L L 8 E moRC COmFORT+3BLE TUAlJ ONE RESTIN6 O N fi Sfl6Rp
SPINY RIDGE.
..
Or( fl FIIIT ONE.h/
3. Explain that new and better fitting denturesmay help many problems.. Misery loves company!
,,,,
a~~ Inform the patient there are about 25 millionUP TOO denture wearers, according to government
E
/ .
APl
LY
/
statistics, and most are satisfied!A soup diet is unnecessary, especially if the patient can learn to chew on both sides at once. The most difficult part is that some patients need
a lot of time to get used to these clumsy objects!
21
4. If the patient has an obvious reduced
vertical dimension there is a need to explain that natural teeth gradually wear down and the chin will move closer to the nose. 'This will occur faster if the patient has been
wearing dentures for a long time. The Natural, normal expression with natural teeth or with artificial dentures when first inserted in the mouth.
result is a bunching of the skin in the lower
-face with resultant wrinkles and depressions.
A 4 mm layer of Bosworth green wax on the lower occlusal surfaces and some on the buccal flanges takes but a few minutes but provides a preview of how this problem can be improved. Don't forget to mention that
~ffect of wearing the same artificial dentures for too
complete elimination of wrinkles by this is
long a period. Wrinkles or depressions form in the
not possible. {Give the patient a Copy of this Upper and lower lips ( A and C). The lips become compressed and protrude ( B ) . The chin moves for-
illustration and explanation). ward and upward and becomes pointed ( D ) . ~h~ cupid's bow loses i t s shape and the lipline straightens
( E ) . Pouches become pronounced on each side of the lower jaw ( F ) . (ADA illustrations)
5. Don't lecture to your patient. Make your comments short and to the point. Be upbeat and never pessimistic. There is a strong basic need, in herent to most, to be liked. The eminent prosthodontist Bernard Jankelson has stated, "If the patient likes you, heishe will like the dentures. If the patient don't like you, the dentures will always be faulty."
Recommended Reading:
"Commurrication In Our Lives", Julie T. Wood, Wadsworth Pub.., basic text used by the USC Annenberg School of Communication.
"How To Win Friends and Influence People", Pocket Books, lnc., '36, $1 2.95 in USC bookstore. One of the most popular (16 million copies) and important books written on self-improvement and practical communication.
SURGICAL CORRECTIONS
-
An assessment of needed surgical correction is made before the final prognosis.1. Muscle attachments that are close to the crest of the ridge are unfavorable to denture stability and retention. Surgical correction in this case is relatively difficult and is usually not done except in extreme cases.
2. Large tuberosities provide good support and retention; however, they must be viewed with suspicion. If deep, bilateral undercuts are present, they should be corrected with surgery. Extremely long tuberosities that can interfere with the mandibular denture can be reduced. Flexible, fibrous areas overlaying tuberosities effect stability and ideally should be surgically excised.
3. Sharp and/or prominent mylohyoid ridges will make it difficult to create a seal in the disto-lingual vestibules. 'This area is especially irr~portant when the ridge is poor but the patient has a Class I or II lateral throat form. A sharp mylo- hyoid ridge is also a potential source of soreness during mastication. Surgical correction is not a difficult procedure.
3. Abnormal soft tissue, usually seen in the upper anterior area, especially if it is a large mass and pendulous, can be easily corrected.
IMPORTANT: There are alwavs potential surgical risks. Make certain there are no medical contra-indications or psychological problems before you get into a discussion with your instructor and patient in this matter.
It is estimated that any competent dentist satisfy about
70%
of the denture wearing patients, 25% can be treated by the experts, while the remaining 5% cannot be successfully treated. If your instructor believes the patient cannot be treated by an under-graduate student, refer the patient to your Group Administrator for referral to Graduate Prosthodontics or ifthey are not able to accept the patient, to the L.A. Dental Society for a list of qualified prosthodontists.Objective: To make an overextended impression of the ridges, vestibules, and underlying bony supporting tissues so properly extended custom impression trays may be constructed. Note: If is impossible to make a correct final impression unless the preliminary impression is properly extended and tray borders are correct.
1. Positioning of the patient: The patient should be seated comfortably in an l~pright position. The ridges should be parallel to the floor, so position -the head rest accordingly.
2. Lubricate the patient's lips lightly with Vaseline.
3. It is usually best to complete the mandibular impression first. This accustoms the patient to the material, there is less apprehension and may prevent or lessen gagging when making the maxillary impression.
MANDIBULAR PRELIMINARY IMPRESSION:
1. Mark the distal ends of the pear-shaped pads with a disposable indelible stick. The pear-shaped pads are usually pale, firm, attached, and stippled.
The retromolar pads are redder, soft, and not attached or stippled. Ask for help
f you cannot locate the end of the pear-shaped pad and 'the beginning of the retromolar pad.
2. Select a tray that extends slightly distal to the marks and has about 5 mm. between the trays and tissue. For the average ridge, use edentulous trays. For a large ridge, it may be an advantage to use dentulous trays.
3. Extend the tray with red utility wax, if indicated. Roi~tinelvplace soft periphery wax on the entire lingual border. This wax requires little or no heating. The wax is not used to extend the tray, but is needed to help displace the tongue and floor of the mouth, and force alginate into the entire lingual vestibule. Seat the tray firrr~ly to adapt the wax. 'Then dry the wax with an air syringe and add a thin layer of alginate adhesive (Hold).
4. lnstruct the patient to rinse vigorously with a mouth wash to remove ropy saliva and possible debris from the mouth; remove with an oral evacuator.
5.
Use about 700 water; a few degrees warmer or colder for less or more workingtime. About 15% less water is used to obtain a thicker mix; this will displace the soft tissues and provide better extensions.
6.
Mixing time depends on the brand of alginate. Mix the alginate for 1 minute for Jeltrate or 30 seconds for Coe. The mix must be smooth and creamy.7. Load the tray so the alginate is evenly distributed and 'completely fills the tray. Load the tray in one minute or less. Don't smooth the surface of the alginate; it's not necessary.
9. A normal amount of saliva will not effect this type of impression as fine detail is not necessary; it's usually not necessary to dry the mouth. If salivation is profuse, pack sponges over the ridge and remove just before seating the tray.
10. SEATING OF TRAY: Stand in front and to the right of the patient. If you are left-handed, reverse these hand positions. Retract the right corner of the mouth with your index finger of your left hand, or use a mouth mirror if the mouth
opening is small. Seat the tray with your right hand rotating the tray against the left corner of the mouth. lnstruct tlie patient to raise the tongue as the
irr~pression is being seated in place (practice with an empty tray). Retract the lips and cheeks and make certain that the alginate is flowing into the vesti- bule and over the edges of the tray. When the tray is seated, release the lip. lnstruct the patient to bring the tongue forward and from side to side so the tip is approximately touching the lingual border of the lip. Hold the tray with your index fingers on the bicuspid region and your thumbs along the inferior border of the mandible.
Im~ortant:'The preliminary irr~pression must also be border molded. Hold without movement for about 1 minute and then manipulate the lips and cheeks so the impression will have better extensions. The tongue movement (above) will also mold the lingual borders. This will make the procedure of outlirling the custom tray rnuch easier and more accurate. Break the seal by reflecting the' lip and remove with a jerk.
11. INSPECTION AND INTERPRtrATlON OF DEFECl'IONS: a. Incomplete coverage
1. Tray too small.
2. Tray not corrected with wax.
3. Insufficient alginate used. b. Metal tray showing:
1. Too much pressure used.
2. Tray too large or too small (metal sticking into the lower slopes of the ridges).
3. Voids (usually in the lingual flange area)
-
the tongue was probably trapped under the lingual flange due to failure to have the tongue elevated when positioning the tray.c. Multiple small bubbles in the alginate: failure to mix 'the alginate thoroughly. The spatula must be forced through the alginate against the side of the bowl.
d. Grainy appearance:
1. Failure to mix the alginate for a long enough. 2. Improper water-powder ration.
3. Water too hot.
12. Handling the impression after removal from the mouth: Wash the acceptable alginate impression with tap water (never use hot or cold water as dimensional changes will occur). If thick ropy saliva adheres to the impression, wash with a solution of plaster and water. Trim any excess alginate with a sharp knife or scissors. Dry the impression by shaking and blotting. Do not use an air syringe.
13. Now is a good time to make the outline for the custom impression tray, using
an indelible stick. The outline is made 1-2mm short of the vestibules and must include the pear-shaped pads. If doing this for the first time, have an instructor make the outline. The indelible stick will transfer to the stone cast.
Immediately wrap the impression in a wet paper towel. Pour no later than 12 minutes.
1. Palpate for the pterygo-maxillary notches with a mouth mirror, and mark this area on both sides with an indelible stick. Ask the patient to say "ah". Note the "ah" (vibrating line) and mark this line with the indelible stick, connecting the hamular notches. To facilitate these marks, dry the mucosa with a
2 X 2 sponge and wet the tip of the stick with alcohol. Bear in mind that the vibrating line is
not
the junction of the hard and soft palate (except a House Class Ill).2. Select a tray slightly past the posterior line and allows a space of about 5 mm. between the tray and tissue.
3 . It is commonly recommended to bead the posterior border with periphery wax. This is not necessary unless the patient is a gagger. If the vault is deep, build up some support with the soft periphery wax to help prevent sagging of the alginate. Seat the tray 'firmly so the wax corrections are well adapted. It is an advantage to practice placing the tray and removing it. Always use the same path of insertion and removal. This also prepares the patient for the
impression.
7.
For your first case, have an instructor check the tray selection and wax corrections.8. Mixing the alginate: The rubber bowl must be clean and dry. Use 10% less 70" water (use 72" or higher if the patient is a gagger). Mix to a smooth creamy consistency; 30 seconds to 1 minute, depending on choice of alginate.
9. Load the tray in one minute or less.
10. If the vault is high, place some excess alginate in 'the center of the palate with your finger to prevent trapping air. If the areas lateral to the tuberosities are large and deep, place some alginate in these areas.
1 1
.
Seating the impression: Stand to the right and slightly behind the patient (if you are left-handed reverse the standing and hand positions). Retract the left corner of the mouth with your left hand or use a mouth mirror if the patient has a small mouth. Retract the lip with an index finger and thumb and seat the tray into the labial vestibule. Then bring the back end of the tray up slowly so thealginate is flowing toward the distal. Stop seating the tray when you can see some alginate along the entire distal tray border. If the tray is overloaded and excess alginate flows onto the soft palate, remove the excess with a fast swipe of your index finger or a mouth mirror.
12. Border molding: Hold the tray without movement for a minute or until initial gelation, and border mold with manipulations of the lips and cheeks. Repeat these manipulations twice.
13. Break the border seal by raising the lip and remove the impression. Inspect for defects and especially for identification of anatomical landmarks and correct extensions.
14. Outline for the custom impression tray with an indelible stick. 'The outline is placed about 1-2mm from the depth of the vestibules and Imm past the vibrating line and hamular notches.
TIPS ON HANDLING PATIENTS THAT GAG EASILY:
1. Make certain to place periphery wax across the posterior border and make certain the wax posterior seal is firmly adapted.
2.
Use 72" or warmer water so the alginate sets faster; you must work quickly. Seat the tray with alginate in the posterior area first rather firmly so no alginate will escape in that direction. Rotate the front end the tray up slowly andraise the lip so the alginate flow toward the anterior and will end in the labial vestibule.
If some alginate flows past the posterior border, remove it with a quick swipe of your index finger or a mouth mirror.
3. Gaggers often salivate excessively so make sure the head is upright or slightly forward. Use a saliva ejector and also give the patient a few paper towels to catch any saliva that runs out. For a severe gagger, shake some table salt on the tip of the tongue just before seating the tray; a distraction device that is often effective, but don't let the patient see you using the ordinary salt shaker.
4. Constant talking and re-assurance are very helpful. Urge the patient to breathe slowly and deeply through the nose. Don't ever use the word "gag" as the word itself is often enough to initiate the reflex.
5.
Remove the impression about one minute after gelation; don't wait the usual three minutes.HANDLING OF IMPRESSIONS AFTER REMOVAL FROM MOUTH:
1. Rinse the impressions with tepid tap water; don't use hot or cold water as you can get dimensional changes.
2. If sticky mucin is present (common on maxillary), rinse the alginate with a solution of plaster and water.
3. Trim any excess alginate with a sharp knife or a pair of scissors.
4. The irr~pressions must be poured within 12 minutes. Wrap one impression with a wet paper towel while doing the other.
POUR IMPRESSIONS IN STONE:
MAXILLARY:
1. Dry the alginate impression by shaking and blotting; do not dehydrate. It is not necessary to box tl- is irr~pression.
2. Mix the stone to a heavy consistency using a technique to minimize air bubbles Hold the impression against the vibrator with one hand tipping it toward the
anterior. Place a small amount of stone on one posterior end and allow the stone to flow around to the other side.
3. Place a mound of stone that is at least 12 mm. thick and about 6 mm. wider than the impression. This base must have a heavy consistency or it will not support the weight of the tray. Invert the filled impression tray on this stone base. Center it carefully and jiggle it a little to avoid trapping air. Make certain the base of the impression tray is parallel with the table top. Work the stone along the borders to make it extend about 6 mm. beyond the impression and level with the borders. Make certain to reniove all stone that over the metal tray. It is difficult to remove a tray that is "locked in" with stone, often resulting in broken casts.
MANDIBULAR:
1. Same procedures as above except make certain the lingual land area is
smooth and 'l'lat, and level with the lingual alginate border. It is very difficult to separate the impression if the lingual border of the tray (or any border) is locked with stone.
2. The impression and stone cast are covered with a wet paper towel to prevent drying of the alginate.
3.
Allow the stone to set for 20 rr~inutesuntil the heat has been dissipated. Separate the impression tray from the cast in thirty rr~inutes or not more than one hour. Never keep the stone cast in water afterwards as artificial stone is soluble in tap water.IMPORTANT: Don't "bury" the impression trays in a mass of stone as it results in an excessive amount of time and energy to separate and trim.
FINAL TRIMMING OF CASTS:
1. Trim the excess stone with the model trimmer. The usual land areas are not needed. The cast is trimmed to the depth of the vestibules. The only land areas are posterior to the ridges and are 4-5mm wide. 'The lingual land area is
level with the depth of the lingual vestibules. 'The land areas have no height so as to facilitate the fabrication of the custom trays.
2. The mandibular base should be a
full
base and not the "U" shaped cast used for fixed restorations. The bases should be about 13mm thick, at thinnest area.3. Small excesses of stone from air bubbles can be flicked off. Try not to mar or scratch the ridge surfaces.
FABRICATION OF THE CUSTOM IMPRESSION TRAYS:
Objective: To fabricate individualized final impression trays as an aid to correct coverage of the ridge, development of the border seal, and even distribution of the final impression material.
Materials Needed:
1. Tray resin 7. Arbor band and chuck
2. Vaseline 8. Carbide resin bur
3. Plaster spatula 9. Rag wheel on a spiral chuck
4. Paper mixing cup 10. Wet pumice
5. Lead pencil 11. Mounted handpiece
6. Sharp knife 12. Rolletteboardandroller
Note: The custom tray must be RIGID. It must have a handle that does not interfere with the tongue and lips and can be grasped securely. A handle that is too large or long is clumsy to use and uncomfortable for the patient.
1. 'The tray outline will either be present if placed with the indelible stick in the alginate impression or it can be drawn on the cast with a pencil. The tray outline is a very critical step and should be seen by an instructor.
a. About 2 mm. short of the vestibule and frenulae.. b. To the distal aspect of the pear-shaped pad. c. I mm. distal to the upper posterior border.
2. Block out any undercuts with pink baseplate wax. Do not over-block as the borders of the tray will be too far from the vestibules for correct border molding. Im~ortant: If the ridge is thin, most often the lower, make certain to flow pink baseplate wax along the sides of the thin areas. If not done, the thin part of the ridge will break when separating 'the final irrlpression from the master cast.
3. Lubricate the cast (ridge, vestibule depth, and land areas) with Vaseline.
4. Mix the self-curing tray resin in a paper cup, following the manufacturer's directions for measuring the amount of liquid and powder.
5.
Wait until the resin reaches a putty-like consistency.6. Mandibular tray: Lightly Vaseline your fingers and the Rollette board and roller. Mold the resin into the shape of a "hot dog". Place it on the thick side of the Rollette board and roll out to a uniform thickness. Adapt the wafer over the cast with your fingers. To prevent thin areas, do not press too hard. Remove the excess material with a sharp knife or scissors. Keep adapting by quickly moving your fingertips over the entire tray area until initial polymerization takes place (rise in temperature).
7.
Make a small mix for a handle. The handle should take the place of the centrals and laterals in length and width (see drawing above). The anterior handle should be no lonaer than 10-12 mm. 'The length of the handle measures 25 mm. from the edge of the labial border to 'the top. The width should be about 12 mm.-
no more. A handle made this way will enable you to securely grasp the tray and it will not interfere with the tongue and lips.Wet the anterior tray area with monomer so the handle will be securely attached. The handle must be finger supported until almost hard. Wait until the resin is hard and cool (about 15 to 20 minutes) before removing the cast.
8. Maxillary tray: The procedures are similar to above except the resin is formed to the shape of a flat ball before rolling out on the board. Roll out the wafer (begin from center and roll to the sides) so it is the approximate shape of the cast. The handle should have the same length of 25 mm from the edge of the labial border to the top and the other stated dimensions.
9. Trimming the trays: The gross excesses are removed with an arbor band and then perfected with resin burs in a handpiece. Polish the top and sides with pumice. The tray borders must be 2 rrlm thick (nothinner), rounded, and smooth.
NOTE: ALL LABORATORY WORK USED IN THE MOUTH SHOULD BE NEAT AND CLEAN AND SHOULD REFLECT THE OPERATOR'S SKILL AND ABILITY. THIS IS VERY NECESSARY FOR THE PATIENT'S COMFORT AND WILL GAIN
FINAL
IMPRESSIONS
Materials Needed:
1. Mouth mirror 8. 3/32 twist drill or No.8 round bur
2. Pan with cold water 9. Melite resin bur
3. Compound heater 10. Light-bodied rubber base
4. Stick compound 11. Mixing pad and spatula
5. Alcohol torch 12. Indelible stick
6. Vaseline 13. Sham knife
7. 2 x 2 sponges 14. Ceramic tile or glass slab
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Note: The denture manual must be open for reference.If possible, the old dentures should be left out of the mouth 24 hours before the final impression. Unfortunately, many patients will not heed this request. If the patient has large areas of inflamed or distorted mucosa, the use of tissue conditioning, a special soft lining that is placed in the old dentures, may be indicated. Using tissue conditioning is an excellent procedure but increases time and costs. Discuss with an instructor if the mucosa is inflamed and requires either tissue conditioning or leaving the dentures out for a specified time.
BORDER MOLDING
-
GENERAL INFORMATION:Objective: To obtain a peripheral seal for good retention and proper extensions for good support. Ideally, the impression borders should be similar in thickness and length to the final denture borders. 'The borders of the custom impression trays are border molded until the tray has an adequate peripheral seal. This step is
absolutely necessary for dependable and consistent results. Waxes, self-curing resin, heavy-bodied thiokol rubber, and various elastic materials have been
successfully used for border molding. Stick compound takes a little more time and experience, but is an excellent material for students and the material of choice by many prosthodontists.
The patient should be seated in a comfortable position. The jaws should be parallel with the floorso the chair should be almost upright for the maxillary impression and somewhat reclined for the mandibular impression.
The border molding is done in sections by using certain patient movements, manually manipulating the lips and cheeks, or a combination of both. There is
no
research or clinical data to state that superior results are obtained if done with patient movements (called the functional or physiologic method) or manually manipulating the lips and cheeks. The more cooperative patient can functionally mold the borders well under proper supervision. Other patients cannot follow directions easily and manipulation of the lips and cheeks by the dentist is necessary. 'The choice depends on the dentist.INSTRUCTIONS ON THE USE OF IMPRESSION STICK COMPOUND:
1. When heating the compound over a 'flame, soften only the very end. Iftoo large an area is softened, the whole stick starts to sag and becomes hard to handle.
Do not soften in the water bath! Hot water will leach out some of the ingredients and will change the physical properties.
2.
To prevent long strings after adding compound, pull the stick away a little, getting a short string. Wait a moment for this thin string to cool. Then quickly pull away and the compound string will break.3 . When building LIP a border, over-build, allowing the patient's musculature
andlor your manipulations to push away the excess. Attempt to apply the compound evenly. If the addition is uneven, mold the compound to an ideal form with your fingers. Lightly lubricate your (gloved) fingers with Vaseline to
avoid having the material adhere.
4. After heating the border area with an alcohol torch, temper for a few seconds in 140" water. An exact temperature is not critical but the water should be hot. Tempering distributes the heat in the compound and the wet surface lessens the possibility of discomfort.
USE OF HEAVY-BODIED PUlTY FOR BORDER MOLDING:
The use of vinyl polysiloxane putty evolved in recent years so border molding could be done with less time and effort. The procedures for using putty are quite different than for compound.
ADVANTAGES:
1. Armamentarium is simpler as a pin point flame and water bath are not needed.
2. No fear of patient discomfort from the heated compound.
3. More working time than compoound (about 5 min depending on brand).
4. Possible to border mold much larger sections. Deficiencies can be corrected witha small mix of putty.
DISADVANTAGES:
I . The putty will not adhere to the tray without an adhesive.
2. 'The putty can not be extended as far as compound and an accurate preliminary impression is necessary, i.e., one that captures all the supporting areas and extended into the vestibules.
HANDLING PROCEDURES:
1. The custom tray must be about 2mm short of the attached movable tissues, held under moderate tension. If any area is short (4-5 mm) it must
be
corrected withcompound. If there are too many short areas, check with your instructor as a new preliminary preliminary impression and new tray may be needed.
2. Locate the "ah" line and mark it with an indelible stick, then Insert the tray firmly and the "ah" mark will transfer to the tray. The tray is reduced so it is Imm
distal to the line. Immrtant: A distal border that is short must be corrected with compound or tray resin.
3. The tray is dried and the borders painted with putty adhesive. Add additional adhesive half way down the sides of the buccal and lingual for better bonding.
4. Mixing: The putty comes in two colors and will be dispensed in measured amounts or in bulk containers. For the latter, use a tongue blade to remove the approximate amount needed (the measuring spoons are too wasteful). Use a different tonaue blade for each color as the same one would contaminate the entire amount.
5.
Use vinyl gloves to mix. Complete the mix in 45 seconds. Roll out putty and make2 -3 "worm-like" forms of about 3mm in diameter and 40mm in length. Plan on completing the border molding in 3 sections. Later these can be reduced to two or even one.
6. Immediately start border molding with firm manipulations, as putty does not flow as easily as compound. Continue to manipulate the lips and cheeks, and tongue movements for lower, for about 3 minutes.
7. Remove in 5 minutes. Borders that are too thick are reduced with a s h a r ~ knife. Short areas are corrected with a small mix of putty (adhesive not required).
Evaluate for seal and extensions.
8. Final impression can be completed with rubber base (adhesive needed) or light-
